The present invention relates to a winding fixing structure of a rotary transformer-type resolver, and more particularly to a winding fixing structure that secures a crossover that connects a rotary transformer output winding and resolver excitation windings of a rotary transformer-type resolver.
Among rotary transformer-type resolvers that perform AC excitation of the resolver rotor, there are conventional resolvers in which a rotating coil and resolver rotor are secured to the rotary shaft, and the rotating coil and the resolver rotor coils are respectively bound by cord and secured by a compound (for example, see FIG. 2 of Japanese Unexamined Patent Application Publication S63-318725). In addition, there are resolvers in which a printed wiring board is located between the rotation side coil and the resolver rotor coils. The terminal of the rotation side coil is connected by solder to a through hole formed in the printed wiring board, and the terminal of the rotor coil, which is wound around the resolver rotor, is connected to the same through hole (for example, see FIG. 1 of Japanese Unexamined Utility Model Application Publication H5-4427).
In addition, as shown in FIG. 13, there are known resolvers in which a wire (referred to herein as a crossover) that connects the rotary transformer output winding 65 and the resolver excitation windings 64 is soldered, the crossover is covered with an insulating tube 6, and the crossover, which has been covered with the insulating tube 6, is secured to the rotary shaft 68 by a cord 61. The resolver shown in FIG. 13 includes a resolver stator 71, which has resolver stator windings 70, and an outer core 66, which has a stator transformer winding 67. A shield plate 69, which shields against magnetic flux leakage from the outer core 66, is oriented radially between the resolver stator 71 and the outer core 66. In addition, a resolver rotor 63, which has resolver excitation windings 64, and an inner core 62, which has a rotary transformer output winding 65, are located adjacent to one another on the rotary shaft 68. The resolver excitation windings 64 are mutually connected from the rotary transformer output winding 65 with a crossover. The respective lead wires are soldered at the crossover, which is covered with an insulating tube 6, and the crossover is secured to the rotary shaft 68 by a cord 61.
However, in the resolver of Japanese Unexamined Patent Application Publication S63-318725, no treatment of the crossover is performed, which reduces the reliability of the resolver. In addition, in Japanese Unexamined Utility Model Application Publication H5-4427, the terminal of the rotation side coil and the terminal of the rotor coil wound around the resolver rotor are directly connected to the same through hole, and the wire that is between the rotary shaft and the through hole extends for a substantial distance. As a result, when used in a severe usage environment, such as in an automobile that has vibration, the crossover may become loose, disconnected, or may cause a short circuit.
In addition, as shown in FIG. 13, when the respective lead wires are soldered at the crossover, which is covered with the insulating tube 6, and the crossover is secured by means of a cord 61 to the rotary shaft, it is difficult and time consuming to tightly bind the crossover with a cord 61, because the space between the rotary transformer output winding 65 and the resolver rotor 63 is narrow. The outlets of the resolver excitation windings 64 are determined by the number of magnets, the phase of the drive voltage, etc., and when the rotor is secured to the rotary shaft 68, the outlets of the resolver excitation windings 64 are uniquely determined with respect to the rotary shaft 68. The rotary transformer output winding 65 is connected to the resolver excitation windings 64 with the crossover, but if the position of the rotary transformer output winding 65 with respect to the rotary shaft 68 is not taken into account, the length of the crossover may increase. As a result, even if the crossover is secured by a cord 61, the crossover may come into contact with the inner core 62, the resolver stator 71, or other parts, which may result in disconnections.